天然气净化厂Cansolv尾气处理装置废水处理

Wastewater treatment by Cansolv exhaust gas treatment device in natural gas purification plant

关键词:  天然气净化厂  Cansolv  尾气处理  APU废水  O₃氧化  O₃耦合催化剂氧化  O₃/H₂O₂氧化 

Key words:  natural gas purification plant  Cansolv  exhaust gas treatment  APU wastewater  O₃ oxidation  O₃ coupled catalyst oxidation  O₃/H₂O₂ oxidation

摘要:

目的 解决Cansolv尾气处理装置胺液净化单元(APU)废水高盐、高有机物与还原性硫的高浓水质特征影响水处理系统的稳定运行问题。方法 详细分析了两个天然气净化厂的文丘里和APU废水的水质特征,其中,APU废水成分复杂,是影响水处理系统稳定运行的关键。采用臭氧(O₃)、O₃耦合催化剂、臭氧/双氧水(O₃/H₂O₂) 3种氧化技术处理APU废水,通过废水中COD值和TOC值变化来评价有机物降解效果,研究了反渗透膜污堵原因和O₃/H₂O₂降解有机物机理。结果 O₃/H₂O₂氧化技术为去除废水中有机物的最优方法,当200 mL废水中O₃质量浓度为22 500 mg/L、H₂O₂投加量为2 mL、反应时间为60 min时,达到最佳处理效果,COD去除率为60.8%。结论 采用O₃/H₂O₂协同氧化APU废水,能完全去除水中还原性硫,有效降低有机物含量,从而有效解决膜提浓装置污堵和蒸发结晶装置堵塞起泡问题。 

Abstract:

Objective The aim is to develop the treatment technology for the amine solution purification (APU) unit wastewater from the Cansolv exhaust gas treatment device, which is characterized with high concentration of salinity, organic matter and reducing sulfur and would affect the stable operation of the water treatment system. Methods The water quality characteristics of Venturi and APU wastewater from two natural gas purification plants were analyzed in detail. The complex compositions of APU wastewater were the key factors to affect the stable operation of the water treatment system. Various advanced oxidation technologies including ozone (O₃), O₃ coupled catalyst, and the mixture of ozone/hydrogen peroxide (O₃/H₂O₂), were used to treat APU wastewater. The degradation effect of organic matter was evaluated by the changes in chemical oxygen demand (COD) content and total organic carbon (TOC) content in the wastewater. The causes of reverse osmosis membrane fouling blockage and the O₃/H₂O₂ degradation mechanism of organic matter were studied. Results O₃/H₂O₂ was the optimum method to remove organic matter from wastewater when the O₃ concentration was 22 500 mg/L in 200 mL wastewater, H₂O₂ dosage was 2 mL and reaction time was 60 min, the best treatment effection was achieved, and the COD removal rate was 60.8%. Conclusion sThe O₃/H₂O₂ oxidation can completely remove the reducing sulfur and effectively reduce the organic matter content in APU wastewater, furthermore solve fouling and blocking problems of the membrane concentrator and evaporation crystallization unit.